Add simple script to dump the certv3 content set extension

dump-extn.rb

@@ -0,0 +1,21 @@
+#!/usr/bin/ruby
+
+require 'openssl'
+
+def extension_from_cert(cert, extension_id)
+    x509 = OpenSSL::X509::Certificate.new(cert)
+    extensions_hash = Hash[x509.extensions.collect { |ext| [ext.oid, ext.to_der()] }]
+    asn1_body = nil
+    if extensions_hash[extension_id]
+      asn1 = OpenSSL::ASN1.decode(extensions_hash[extension_id])
+      OpenSSL::ASN1.traverse(asn1.value[1]) do| depth, offset, header_len, length, constructed, tag_class, tag|
+        asn1_body = asn1.value[1].value[header_len, length]
+      end
+    end
+    asn1_body
+  end
+
+
+cert = File.open(ARGV[0], "rb").read
+
+puts extension_from_cert cert, "1.3.6.1.4.1.2312.9.7"